The present invention relates to a selector circuit in a paper feeder for use in a copying machine or the like.
Among the copying machines known theretofore, a number are equipped with a plurality of paper feed trays. Such a machine holds upper and lower trays each capable of storing paper of various sizes. The conventional copying machine of this type may have a control panel where paper-size indicating windows are formed together with the provision of an upper-tray selector switch and a lower-tray selector switch. An operator presses either the selector switches after determining by visual inspection which of the upper and lower trays stores the paper of a desired size.
In this case, it is necessary for the operator to distinguish first the tray that stores the paper of the desired size and then to press the corresponding selector switch according to the result of distinction. Since the desired-size paper may be in the upper tray or the lower tray, the selection operation may be confusing and is liable to be performed erroneously.
In an attempt to eliminate the above described disadvantages, the present invention has been accomplished to achieve improvements by allowing an operator to select a desired paper size directly, the control automatically registering and encoding a signal representative of the selected size, comparing the signal thus encoded with encoded signals representative of the paper sizes in the trays, and checking electrically and automatically whether any of the paper stored in the trays coincides with the desired size, and starting to feed the paper of the coincident size automatically from the corresponding trays or, in case the paper of the coincident size is not present in the tray, indicating such state.
In the above procedure, the operator's work requirement is merely to press a selector switch for the paper of a desired size. In this manner the operation is facilitated and the panel structure is simplified since it requires no more than paper-size selector switches and a "No-Paper" indicator.